Buffer reads from standard input reblocking to the given blocksize
and writes each block to standard output.

Internally, buffer is a pair of processes communicating via a large
circular queue held in shared memory. This means you *must* have a
kernel with

  options SYSVSHM

compiled in. The reader process only has to block when the queue
is full and the writer process when the queue is empty. Buffer is
designed to try and keep the writer side continuously busy so that
it can stream when writing to tape drives. When used to write tapes
with an intervening network, buffer can result in a considerable
increase in throughput.

- Christian "naddy" Weisgerber
  <naddy@unix-ag.uni-kl.de>
